The present invention relates to nozzle plate for an inkjet printer having a nozzle aperture through which ink is dispensed.
It is known in the field of fluid mechanics and in inkjet printing technology that, if a liquid is held in an container and that container has a hole in it with the hole below the level of the surface of the liquid, the liquid will not necessarily leak from the container depending upon the parameters of the liquid and the hole. The parameters which determine whether or not the liquid leaks from the container or not are the size of the hole, the surface tension of the liquid, the surface energy of the material in which the hole is formed, the vertical height of the liquid above the hole and the force of gravity. In inkjet printer systems, for example the so-called "BubbleJet" printers, additional means are used to control the pressure which the liquid exerts on the hole, typically in the form of an open cell foam structure. The surface tension force of the liquid acting in the capillaries of the foam at the liquid/air interface on the external surface of the foam can generate a back pressure which is able to balance the weight of the liquid in the foam.
There can be occasions when it is beneficial to have a large hole or slit in an inkjet printer, but where it is not feasible to use an open cell foam structure in order to exert a back pressure. For example, WO-A-93-11866, PCT/GB95/01215 and WO-A-94-18011 all disclose printing methods where a large slit may be useful.
It is desirable therefore to provide an alternative mechanism for ink retention.